Mid 80's Necklace Silver and Turquoise

Purchased at Gallup NM Flea Market in about 1986 from a Begay family.

All silver components except clasp are sterling. Was told at the time the black beads were coconut shell. The silver beads with seams are hollow, rest are solid. The turquoise has darkened and become a little greener over time.
It is strung on a wire type material.
I would like to change the clasp to something more user friendly.

Can anyone tell me more about this? Would it be considered real or fake? Any thoughts on type of turquoise? Thank you.

It is very tarnished now, but I am afraid to clean it for fear of discoloring the Turquoise. Full length is about 28".

It is a necklace that has been strung from purchasing different beads/material from a supply house. You could have the necklace restrung with a hook and eye clasp put on. We use polishing gloves that would work just fine on the silver beads.